Cam for pot spinning



March 11,1958 T. E. PATTVON ET AL 2,326,036

CAM FOR ,POT SPINNING Filed July 6, 1954 2. SheetsSheet l INVENTORS BY w m ATTORNEY March 11, 1958 Filed July 6, 1954 T. E. PATTON ET AL CAM FOR POT SPINNING 2 Sheets-Sheet 2 a Z 720C DISPLACEMENT nsz ocxrr 210054 FEAT/0A! INVENTORS IYzeadoreEPalim d 51 C. myyizzs ATTORNEY United States Patent CAM FOR POT SPINNING Theodore E. Patton, Enka, and Guy C. Wiggins, West Asheville, N. C., assignors to American Enka Corporation, Euka, N. C., a corporation of Delaware Application July 6, 1954, Serial No. 441,426

Claims. (Cl. 57-77) This invention relates to the pot'spinning of rayon yarn and more particularly to a pattern control arrangement for producing rayon cakes of improved uniformity of wall thickness and permeability.

In pot spinning apparatus, the pot is rotated and the freshly spun thread is laid up in successive courses in the pot by a funnel which reciprocates in a vertical path through the top of the pot. The funnel, which acts as a traverse mechanism, is intended to lay up a cake of uniform wall thickness but it has been found that cakes produced by a conventional pot spinning machine actually have thinner walls at the top and the bottom than they have in the middle. Such cakes are hard to handle without damage and they do not wash well with resulting lack of uniformity in the finished thread.

On the theory that cam follower dwell could be responsible for the difliculties experienced, it has been customary to reverse the funnel very abruptly. This not only did not alleviate the cake wall thickness problems but also so increased vibration of the machine as to shorten its useful life.

It is therefore an object of the present invention to overcome the foregoing difiiculties and to provide means to produce a pot spun rayon cake characterized by equal wall thickness throughout its length while at the same time reducing the overall machine vibrations.

It has been discovered, as an important part of this invention, that the dwell at the change of direction of the funnels may be increased providing that the displacement velocity and acceleration are properly correlated. It is therefore possible to reduce vibration and improve the cake characteristics at the same time. It is likewise proposed as a part of this invention to super-impose the effect of gravity upon the dwell in a manner to cause the effect of gravity to improve the operation of the machine and the uniformity of the cake produced thereby.

Other objects and advantages of this invention will be apparent upon consideration of the following detailed description of a preferred embodiment thereof in which: I Figure 1 is a fragmentary view in end elevation of a two-sided top spinning machine showing a cam, contoured according to the present invention, in its position of use;

Figure 2 is a development of the cam of Figure 1; and

Figure 3 is a chart plotting axial displacement against angular displacement, change in velocity against angular displacement and change in acceleration of the cam followers against angular displacement, or, displacement, velocity and acceleration diagrams, respectively.

Referring now to the drawing in greater detail, the numerals and 11 represent rayon spinning pots of conventional design and operation. Pot 10 is provided with a funnel 12 and the pct 11 with a funnel 13. Funnel 12 is held by a bracket 14 from an operating rod 15. The funnel 13 is held by a like bracket 16 connected to an operating rod 17. At their respective upper ends, the operating rods and 17 are provided with cam followers 18 and 19. The cam followers 18 and 19 are in the form of freely rotatable rollers which travel in a groove 20 in the surface of a cylinder 21.

der 21 is made in two telescoping pieces which define be tween them the groove 20. The cylinder 21 is rotated through a gear 22 by conventional means, not shown. A conventional drive is provided for rotating the pots 10 and 11 and that drive is not shown in the drawings. The groove 20 extends for 360 around the cylinder or drum 21 and the path which the groove follows is depicted in Figure 2. Figure 3 discloses the actual mathematical position of the groove and the effect which it has upon the followers 18 and 19.

The displacement diagram of a conventional cam used in a pot spinning machine has almost a perfect straight line development between changes in direction. In other words, in a conventional pot spinning cam the linear displacement of the funnel per degree of angular displacement of the cam is constant throughout 180 of rotation of the cam. The cam 20 of thevpresent invention, however, is not of straight line development for 180. Dur

ing a number of degrees designated alpha in Figure 3, the displacement is a function of a curve on a radius r, while, during another group of degrees designated beta, the displacement is a function of a curve on a radius r In both directions between alpha and beta the development is along a straight line.

The angle alpha may vary from 5 to 30, while the angle beta may vary from 10 to 60. r, is longer than r, by a ratio of between 1.75 and 2.75 to one. The exact values for r, and r depend on the speed of the machine and the length of the stroke. For a machine having a stroke of 94 mm. with a cam mm. in height and having an outside diameter of 240 mm., rotating at 45 R. P. M., r is equal to 3%. inches, r, to 8 /2 inches, alpha is equal to 22 and beta is equal to 56.

Due to the fact that the radius r; is greater than the radius r the follower operates slower at the top of its stroke than it does at the bottom. This causes more yarn to be deposited near the top of the cake where there is a tendency for it to drift away by the action of gravity and less yarn at the bottom of the cake where there is a tendency to receive yarn drifting in as a result of gravity. The resulting cake is desirably right cylindrical in external configuration and defines a right cylindrical inner space with walls of uniform thickness. The resulting cake is found to have desirable washing characteristics.

What is claimed is:

1. In pot spinning apparatus including a rotating pot and a reciprocating funnel, a 360 cam for controlling the reciprocation of the funnel, the displacement diagram for said cam being characterized by a regular curve controlling the top change in direction of the funnel which is of a longer radius than another curve which controls the change in direction of the funnel at the bottom of its stroke, the displacement diagram for said cam intermediate said curves being substantially of straight line development.

2. In pot spinning apparatus including a rotating pot and a reciprocating funnel, a 360 cam for controlling the reciprocation of the funnel, the displacement diagram for said cam being characterized by a regular curve controlling the top change in direction of the funnel which is of a longer radius than another curve which controls the change in direction of the funnel at the bottom of its stroke, the displacement diagram for said cam intermediate said curves being substantially of straight line development, the ratio of the long radius to the short one being not less than about 1.75 to 1 and not more than 2.75 to 1.

3. In pot spinning apparatus including a rotating pot and a reciprocating funnel, a 360 cam for controlling the reciprocation of the funnel, the displacement diagram for said cam being characterized by a regular curve extending from about 10 to 60 of angular displacement for In actual practice the cylin' controlling the top change indirection of the funnel, said curve being of'a longer radius than another curve which controls the change in direction of the funnel at the bottom of its stroke, the displacement diagram for said cam intermediate said regular curves being substantially of straight line development.

4. In pot spinning apparatus, a rotatable pot, a funnel, and earn following means for reciprocating said funnel in a vertical path the improvement that comprises a cam rotatable through 360 of angular displacement, the displacement diagram far said cam having follower guiding portions of straight line development to control the major portion of the up and down strokes of the funnel and upper and lower connecting portions of regular curved line development disposed 180 apart, the upper connecting portion being greater in degrees of angular displacement of the cam and having its curved line development following a curve of longer radius than the lower connecting portion.

'5. In pot spinning apparatus including a rotating pot and a reciprocatingfunnel, a 360 cam for controlling the reciprocation of the funnel, the displacement diagram for iii said cam being characterized by a regular curve extending for about 10 to 60 of angular displacement for controlling the top change in direction of the funnel, said cam having another curve extending from about 5 to about 30 of angular displacement for controlling the change in direction of the funnel at the bottom of its stroke, the curve controlling the top change in direction being greater in degrees of angular displacement than the curve which controls the bottom change in direction and the radius of the curve controlling the top change in direction being longer than that of the curve which controls the bottom change in direction, the displacement diagram for said cam intermediate said curves being substantially of straight line development.

References Cited in the file of this patent UNITED STATES PATENTS 1,974,482 Bochmann Sept. 25, 1934 2,443,231 Elvin June 15, 1948 2,633,693 Bolton et al Apr. 7, 1953 2,633,694 Rose et al Apr. 7, 1953 

